Prosthetics are going high-tech

Peter Davidson, of Great Plains Rehabilitation Services in Bismarck, plugs in a personal digital assistant into a children's prosthetic leg to read collected data and make adjustments to the digital sensors.

Prosthetist Peter Davidson pulls open a drawer with rolls of fabric.

This fabric is tougher than any fabric found at a craft store. It's like the material used in body armor.

At Great Plains Rehabilitation Services, they use Kevlar to cover the mold that goes over the leg of a missing limb.

It is arranged on the mold "to get exactly what you need for yield strength and tensile strength," Davidson said.

This strength is needed for active people who are without a limb. Combined with newer artificial limb technology, it allows them to keep up to some of the tasks life demanded on them prior to losing the limb.

Some of the newest technology was created because of soldiers losing limbs in combat in Iraq and Afghanistan. By September, there were 833 soldiers who served in Iraq or Afghanistan and had a limb amputated, said Nathan McKenzie, a prosthetist at Medequip One who recently returned from a conference about prosthetics.

Davidson visited with some of the soldiers at the Center for the Intrepid at Brooke Army Medical Hospital in San Antonio, Texas, in June. He saw some of the newest technology in action, as well as a comprehensive way to treat amputees.

"I was really moved by the soldiers," Davidson said. "They gave their all, it took their leg and they're teaching me about the process."

He played basketball with some amputees at the center, and also tried to get up on a surf board in a swimming pool on one leg.

Most people lose a limb because of a vascular disease, but the number of amputations because of trauma is increasing, McKenzie said.

"Out of the traumatic end, you see them younger, usually less than 30 years old," McKenzie said. "Vascular you see typically in older people."

When a person loses a limb - either to injury or disease - it is amputated above or below the knee or elbow. This can affect the person's range of movement. Technology, though is trying to give back some of that movement.

"You don't put a leg on and say, 'have a nice day,'" Davidson said.

It takes time to learn to operate the limb, and it's range of motion is dependent on the technology of the limb. Great Plains Rehabilitation follows up with the patient to help them use the artificial limb, and make adjustments as needed. One change that is usually done on amputees is to change the size of the custom-made socket that fits over the amputated limb after swelling decreases.

The type of artificial limb a person gets depends on many factors. Insurance usually sets caps on what they will spend for an artificial limb, McKenzie said.

Cost and insurance coverage is part of it, but it also depends on what activities a person wants to do, and in some cases, a person may have more than one model. They also can get a cover that goes over the socket and limb mechanisms that resembles the leg or arm.

With hands and feet, more coordination is available than previously because of available materials and technology.

Foot technology provides more realistic movements than hand technology because the fingers on the artificial hand are not as dexterous as real fingers.

Computers are used to recreate some of the finer movements of a hand, foot or joint. With feet, for instance, a computer helps move the ankle and recognize when the artificial foot is used in different situations. The computer components can sense when the artificial foot is on level ground, walking up stairs or getting up from a chair, Davidson said.

This type of foot is suited to everyday tasks, but for people who are athletic or have physically active jobs, there are artificial legs that handle the motion and stress placed on the foot and leg during those activities.

With hands, technology is improving to provide functional fingers and thumbs. There's also research into controlling the artificial limb through muscles in the chest.

"It won't look in five years as it does now," Davidson said about prosthetic technology.